1. Field of the Invention
The invention relates to a tube connection for thin-walled, small-diameter metal pipes and, in particular, for brake lines, for fuel lines, or for hydraulic lines, for motor vehicles, which comprise a sleeve for sealingly connecting a first conically flared metal pipe, with a flare such as ISO 4038, which is set in a bore cone under pressure force of a tensioning body resting against the flare.
2. Brief Description of the Background of the Invention Including Prior Art
Such tube connections are employed in the construction of motor vehicles at locations which are difficult to access because of narrow spaces. Such tube connections have to be formed at these locations with special tools. The higher liquid pressures in the lines and conduits require corresponding sealing seats and corresponding pressure forces on the sealing seats.
An embodiment is known to the applicant, which comprises a sleeve into which two separate sealing seats are pressed, in each case, with a first conically double-flared metal pipe and a second single-conically flared metal pipe, against the sealing seat with screw nuts. The screw nut has to be applied on the two metal pipes before the application of a flare and the screw nut has to be tightened with screwdrivers, or socket drivers. In order to assure a permanent sealing, the screw nuts are provided with a spindle shaft of a corresponding length.
In addition, German Patent Application Laid Open DE-OS 3,416,702 teaches a solution which concerns an undetachable connection between pipes for hydraulic braking plants and which addresses the problem of the required mounting space. This teaching presupposes a fitting sleeve, which is produced with threaded holes according to German Industrial Standard DIN 74235 and which fixes the starting thread depending on the pipe diameter of the brake pipe and its flare. The conventional construction starts for this purpose with a sleeve part which is provided with a profile bore without thread. The bore base of the profile bore is formed corresponding to the pipe flare, and the contour of the bore base with the front cone face of the pipe flare is axially tensioned lockingly and sealingly at the brake pipe by drawing in or tapering of the cylindrical sleeve part of the fitting on the outwardly curved outer circumference of the rear conical section of the pipe flare. At present, the conventional teaching comprises that a pressure-tight sealing connection between the pipe and the sleeve is formed by a radial rolling or squeezing in of the sleeve part. Such a radial rolling or squeezing in requires however a tool which needs substantial space, since the assembler has to actuate the tool precisely in a direction in which no space is available. In addition, a roll-off motion is particularly difficult to be performed in narrow quarters. Finally, it is disadvantageous in the context of such a teaching, that the rolling of the outer sleeve cannot be performed without straining or stressing the flared pipe itself. For this purpose, the conventional teaching in addition proposes a form-locking and tight reinforcement or armament ring for the guiding at the outer diameter of the braking pipe at the outer circumference of the pipe flare in the rolling region for supporting and/or sealing.